Pump



Oct. 28, 1930. w. MCK. BRAYBROOKS ,8

PUMP

Filed. Nov. 21, 1928 WILLIAM HK BRAYBROOKS gmentoz HP; ak

Patented Oct. 28, 1930 UNITED STATES PATENT OFFICE WILLIAM MICK. BBAYIBROOKS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO GULF OIL BURNER COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OI PENNSYLVANIA PUMP Application filed November 21, 1928. Serial No. 320,967.

This invention relates to improvements in pumps and advantageously in pumps for oil heating apparatus; and more particularly-it relates to a means for draining the pump upon discontinuance of operation of that type of pump which mixes oil and air and discharges the mixture to a burner. I

A common type of oil heating system is one in which the oil is forced through a burner nozzle in company with a proportioned quantity of air. When the operation, of such a system is discontinued there is ordinarily drainage back into the pump of a substantial amount of oil from the suction and discharge lines, and if this oil is not removed from the pump before the apparatus is again put in operation there will e a large slug of liquid oil delivered to the burner nozzle at the very outset of the pumping operation. Such a slug of oil is not accompanied by its proper roportion of air and it is delivered to the com ustion chamber before the surrounding parts have attained a sufiicient temperature to ignite it. Burner nozzles provided for burning an oil-air mixture would not, in an event, discharge such a slug of oil in readi y ignitable form and it would immediately fall to the bottom of the combustion chamber and generally interfere with the desired operation of the burner.

By the invention here disclosed I provide a means for automatically draining all oil from the pump at the end of a run and automatically disposed of this oil when the system is started again. This invention is applicable to all'types of pumps.

In the accompanying drawing I have shown one form of a specific embodiment of my invention. The figure is a segmental longitudinal section.

In this drawing 1 is a pump of a well known type in which'a cylmdrical piston 2 having a straight 1e 3 is revolved eccentrically about the sha 4 by the cam 5 in the cylinder 6. 7 and 8 are the suction and discharge res ctively of the pump. With the rotating 0 the piston 2 in the cylinder 6, the leg 3 slides back and forth through an axially movable closure piece 9. A port 10 in the hollow leg 3 permits ingress of material from suction line 7 to the pump cylinder 6. A sump 11 is provided below the working part of the pump and a small orifice 12 connects through tube 13 from the cylinder to the base of the sump 11. A passage 14 leads from the sump to the discharge line 8.

When operation of the pump is discontinued all oil from the walls of the cylinder 6 and of the suction and discharge lines drains through cylinder 6 and orifice 12 and tube 13 to the sump 11, where it remains until the pump is again started. It will be seen that this permits the pump to start free from any accumulated mass of oil therein which would otherwise be discharged in liquid form, instead of vapor form, upon starting.

The accompanying drawing shows the sump 11 partly'filled with oil, as it will be when, after use, the pump is again put in operation. The direction of rotation of the piston 2 in' the accompanying drawing is clockwise and the orifice 12 is subject to a pressure from the pump side from the time the piston 2 leaves the position shown until it has, in its rotation, passed over the orifice 12. From that time on until the completion of a rotation, the orifice 12'is subjected to a suction from the pum side. So long as there is oil in the sump su cient to submerge the lower end of tube 13, the oil-air mixture being pumped will pass through the orifice 12, the tube 13, up the body of oil in the sump 11, and out throu h the connection 14 during that portion of t e rotation which subjects the orifice 12 to a ressure from the displacement chamber. uring this portion of the stroke a part of the material pumped passes out throu h this indirect channel and 1t suffers no 0 ange in so doing. During that portion of the stroke which subjects the orice 12 to suction from' the displacement chamber, oil is drawn up through the tube 13 and the orifice 12 into the pump cylinder 6. The orifice 12 may advantageously be of such a size as to give an atomizing effect to the oil drawn throu and this oil then becomes a portion of t e material pumped out through discharge 8 on the next pressure stroke; While oil is being drawn up through tube 13 and orifice 12 the connection 14 permits entry of vapor to the sump to displace the withdrawn oil and by equalizing the pressure between the discharge line and the sump it assists the return of oil through the orifice.

It will be seen that so long as there is suflicient oil in the sump 11 to cover the lower end of tube 13 no disadvantage whatever is suflered While the orifice is under pressure and a great advantage accrues while the orifice is under suction. When the pump has been operating a while and all oil has been removed from the sump 11, and the lower end of tube 13 is no longer sealed in liquid in sump 11, a small amount of oil-air mixture may by-pass from the discharge to the suction side of the pump during the intervals when orifice 12 is subject to suction, but this is not always serious and may advantageously be entirely eliminated by a secondary mechanism closing the connection 13 when the level of-oil in the sump 11 becomes insufficient to seal the lower end of tube 13. Such a secondary mechanism is illustrated in the accompanying drawing. The lower end of tube 13 is formed to provide a seat for a closure piece 16 operated through the fulcrumed lever 17 by the float 18. It will be seen that as the level of liquid in the sump 11 becomes little more than suificient to cover the open end of the tube 13, the float 18 falls to a positionwhere the closure piece 16 is brought up against the seat at the bottom of the tube 13. No particular pressure of the closure piece 16 against the end of the tube 13 is required or desirable. The pressure at this point must always be sufliciently slight to permit the flow of oil by gravity from the tube 13 to the sump 11.

Pumps equipped with my invention can advantageously be so placed that the entire system drains into the sump here provided.

Obviously, in the case of pumps having'a plurality of displacement chambers, a separate drain to the sump can be provided from each displacement chamber.

The term displacement chamber is here used to include that portion of all pumps which houses the piston or the impeller.

What I claim is:

1. In a pump for pumping liquid fuel and air in proportioned amounts to a burner, a displacement chamber, a sump, a drain at a low point of the chamber leading into the sump, a tube leading from the drain to a low point in the sump, a valve for opening and closing communication between the sump and the displacement chamber depending upon the level of oil in the sump and a float for controlling said valve for admitting passage of oil or oil-air mixture from the connecting tube into the sump while preventing the flow of anything except liquid from the sump to the displacement chamber.

2. In a pump for pumping liquid fuel and air in proportioned amounts to a burner, a

suction line, a discharge line, a displacement chamber, a sump, a drain in the lower portion of the chamber in communication with the sump, a tube leading from said drain to a low point in the sump, and means for obtaining free communication between a high point in the sump and the discharge side of the pump, comprising a tube terminating at one end in the discharge side of the pump and out of contact with the walls thereof, extending outside of the cylinder of the pump, and terminating at the other end at a high point in the sump.

3. In a pump for pumping liquid fuel and air in proportioned amounts to a burner, a displacement chamber, a sump, a drain in a low portion of the chamber and leading to the sump, a tube leading from the drain to a low point in the sump, a vent to the sump for displacing withdrawn oil, and a valve opening and closing communication be ween the sump and the displacement chamber, and a float for controlling said valve depending upon the level of oil in the sump for admitting passage of oil or oil-air mixture from the connecting tube into the sump while preventing the flow of anything except liquid from the sump to the displacement chamber.

4. In a pump having a suction and discharge side, a displacement chamber, a sump, a passage leading from a low point of the chamber to the sump, a tube in communication with said passage leading to a low point in the sump, and an additional passage leading from a high point in the sump to the outside of the sump and around and outside of the displacement chamber and into the discharge passage beyond the displacement chamber.

5. In a pump having a discharge and suction side, a displacement chamber, a sump,

means comprising a tube for draining liquid from a low point in the displacement chamber to a point below the level of the liquid in the sump and means for conducting air or gas from the point above the liquid level in the sump to the outside of the sump and outside of the displacement chamber and into the discharge passage beyond the displacement chamber.

6. In a pump for pumping liquid fuel and air in proportioned amounts to a burner, a displacement chamber, a sump, a drain at a low point of the chamber leading to the sump, a tube leading from'the drain to a low point in the sump, and an oil actuated valve in the tube for opening and closing communication between the sump and the displacement chamber.

In testimony whereof, I have fixed my signature.

WILLIAM McK. BRAYBROOKS.

hereunto af- 

